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 * The Universal Permissive License (UPL), Version 1.0
 *
 * Subject to the condition set forth below, permission is hereby granted to any
 * person obtaining a copy of this software, associated documentation and/or
 * data (collectively the "Software"), free of charge and under any and all
 * copyright rights in the Software, and any and all patent rights owned or
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
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 * This license is subject to the following condition:
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 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
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package com.oracle.truffle.jx.runtime;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.TruffleLanguage;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.interop.InvalidArrayIndexException;
import com.oracle.truffle.api.interop.TruffleObject;
import com.oracle.truffle.api.interop.UnknownIdentifierException;
import com.oracle.truffle.api.library.ExportLibrary;
import com.oracle.truffle.api.library.ExportMessage;
import com.oracle.truffle.api.profiles.BranchProfile;
import com.oracle.truffle.api.strings.TruffleString;
import com.oracle.truffle.jx.JanivaLang;
import java.util.HashMap;
import java.util.Map;

@ExportLibrary(InteropLibrary.class)
@SuppressWarnings("static-method")
final class FunctionsObject implements TruffleObject {

  final Map<TruffleString, JXFunction> functions = new HashMap<>();

  FunctionsObject() {}

  @ExportMessage
  boolean hasLanguage() {
    return true;
  }

  @ExportMessage
  Class<? extends TruffleLanguage<?>> getLanguage() {
    return JanivaLang.class;
  }

  @ExportMessage
  boolean hasMembers() {
    return true;
  }

  @ExportMessage
  @TruffleBoundary
  Object readMember(String member) throws UnknownIdentifierException {
    Object value = functions.get(JXStrings.fromJavaString(member));
    if (value != null) {
      return value;
    }
    throw UnknownIdentifierException.create(member);
  }

  @ExportMessage
  @TruffleBoundary
  boolean isMemberReadable(String member) {
    return functions.containsKey(JXStrings.fromJavaString(member));
  }

  @ExportMessage
  @TruffleBoundary
  Object getMembers(@SuppressWarnings("unused") boolean includeInternal) {
    return new FunctionNamesObject(functions.keySet().toArray());
  }

  @ExportMessage
  boolean hasMetaObject() {
    return true;
  }

  @ExportMessage
  Object getMetaObject() {
    return JXType.OBJECT;
  }

  @ExportMessage
  boolean isScope() {
    return true;
  }

  @ExportMessage
  @TruffleBoundary
  Object toDisplayString(@SuppressWarnings("unused") boolean allowSideEffects) {
    return "global";
  }

  public static boolean isInstance(TruffleObject obj) {
    return obj instanceof FunctionsObject;
  }

  @ExportLibrary(InteropLibrary.class)
  static final class FunctionNamesObject implements TruffleObject {

    private final Object[] names;

    FunctionNamesObject(Object[] names) {
      this.names = names;
    }

    @ExportMessage
    boolean hasArrayElements() {
      return true;
    }

    @ExportMessage
    boolean isArrayElementReadable(long index) {
      return index >= 0 && index < names.length;
    }

    @ExportMessage
    long getArraySize() {
      return names.length;
    }

    @ExportMessage
    Object readArrayElement(long index, @Cached BranchProfile error)
        throws InvalidArrayIndexException {
      if (!isArrayElementReadable(index)) {
        error.enter();
        throw InvalidArrayIndexException.create(index);
      }
      return names[(int) index];
    }
  }
}
